Internal-combustion engine cooling system



INTERNAL-COMBUSTION ENGINE COOLING SYSTEM Jacke Waer Cooler T.v J. BAY

Filed April 6, 1943 Jaalr Wafer gozer- Vig@ INVENTOR in the Vicinity of the Aleutians.

Patented Dec. 19, 1944 UNITED `STATE s PATENT orifice 2,365,166 m'rERNAL-coivrUsTIoN ENGmE COOLING.

SYSTEM i Thomas J. Bay, United States Navy Application April 6, 1943, serial no. 481,983 s claims. (c1. 12s-174) (Granted under the act of March 3, 1883, as

amended April 30,1938; 370 0. G.

particularly true in the canse of high speed Diesel engines and it has been definitely established that engine deterioration is very rapid whenever opcooling the engine lubricating oil. Sea water is circulated through these heat exchangers as the coolant; the usual arrangement providingk for series flow of the sea water, first through lubricating oil heat exchanger and thence through the jacket water cooler.

A somewhat less common engine cooling system provides'for cooling the engine jacket wa- 4ter,l as described above, but instead of circulateration proceeds with either lubricating oil `or ilafke; water circulating at a temperature below The principal object of the' present invention l-is to avoid the difficulties encountered by lthe use of sea water circulation through the lubri- `eating oil cooler and take maximum advantage of circulating jacket water through such cooler for rapid heating of the chilled lubricating oil upon starting cold engines and, in addition, proi viding for automatic control of the temperatures of the lubricating oil and jacket water withinthe optimum operating range, as specied by the engine designer, regardless of variations in the power at ,which the engine is operated or.

variations in the temperature of the sea water. lWith these and other objects in view as` well as ,other advantages thatmay be incident to ing sea water through the lubricating oil cooler the cooled jacket water is employed as the cooling medium. This type of cooling system has the advantage 'of exposing onlyone of the two heat exchangers or coolers to the corrosive action of sea water andthe further advantage that, upon starting a cold engine, the engine andthe lubricating oil and jacket water temperatures are elevated to the proper operating range much more rapidly than when the'colder sea water isA the use of the improvements, the invention consists in the parts and combination thereof hereinafter set 'forth and claimed, with the under- Y' standing that the several necessary elements constituting the same may be varied in proportion and arrangement without departing from the nature and scope of the invention, as deiined in the appended claims.

In order to make the invention more clearly understood,y there are shown in the accompanycirculated through the lubricating oil cooler.

This type of cooling system has the disadvantage of requiring the use of somewhat larger heat exchangers' for a given installation which to some extent offsets the advantages derived therefrom.

However, the advantage obtained by circulating jacket water through the lubricating oil cooler, that is to say the initial rapid heating of the engine lubricating oil and maintenance of optimum lubricating oil temperature during operation, has become extremely important in view of current operations of Diesel engine propelled naval vessels in the Iceland-North Sea area` and Reports received from vessels operating in these areas and not equipped for jacket water ,circulation through the lubricating oil coolers indicate that in many cases the chilled engine lubricating oil never reaches the proper operating temperature even after hours of engine operation, resulting in accelerated wear of all bearing surfaces, early en-l gine failure, decreased reliability and excessive maintenance and repair requirements. This is ing drawing means for carrying the invention into practical use, without limiting thel improvementsin their useful application to the particular construction, which, for the purpose of explanation, have been made the subject of illustration.

The single figure of the accompanying drawing is a diagrammatic view ofa system of automatically controlling the temperature of the lubricating oil and jacket waterV of an internal combustion engine wherein the jacket water isemployed'to control the temperature of the lubricating oil. l l L -Referring to the drawing, a system for controlling the temperature of the lubricating oil and jacket water of an internal combustion engine` is shown as comprising generallyan engine i0, a jacket water cooler Il and a lubricating oil cooler' I2. The jacket Watercooler Il is provided with a heat transfer'element I3 through which sea water is circulated from a pipe i4 and valve I5 and from which thev sea water escapes through apipe I6. This cooler is also shown as being provided with a heat transfer element il changer.

2 through which jacket water to be cooled is supplied from the engine through a pipe I8 and a three-way thermostatically controlled valve lil.

The .cooled jacket water escapes from the heat` through a pipe 25.

Jacket water from the engine l0 is at times lay-passed around the jacket water cooler Ii through a by-pass pipe '26 and the three way valve I9, the control element 21 of which is placed in thermal contact with the jacket water leaving the engine, as indicated at 28. The utility and operation and function of this by-pass will be hereinafter explained. The sole purpose of the flow control valve I is to protect the jacket water cooler from excess flow of sea water and the same purpose can be served through the provision of a circulating water luy-pass around this cooler.

Lubricating oil from the engine may also beI by-passed around the lubricating oil heat exchanger and directly back to the engine through a by-pas's pipe 29 and an automatic spring loaded pressure relief valve 30 when the engine is initially started. The by-pass pipe 29 can be arranged to by-pass other parts of the engine lubricating oil system as well as the heat exchanger I2, such as' lubricating oil filters, strainers, etc. Thermometers 3| and pressure gauges 32 may be provided wherever desired.

In operation of this newly devised system the three-way temperature control valve I9 is first adjusted to by-pass the cold jacket water cooler Il when the engine is initially started. With the engine in operation, the jacket .wateris heated very rapidly because this waterfis by-passing the jacket water. cooler. This heated jacket water passing through the lubricating oil cooler provides for'rapid heating o! the chilled lubrieating oil circulating through the oil heat ex- In this connecten, it will be understood that in most types of internal combustion engines the temperature of the jacket water and lubricating oil circulated to and from the engine remains absolutely constant regardless of all changes in the temperature or quantity of the seawater circulated through the jacket water cooler. This is readily apparent by reference to the drawing. At constant engine power, heat dissipated to and from the oil and jacket water in the engine and the heat exchangers or -coolers is constant, therefore; with a constant engine jacket water discharge temperature, the temperature of the jacket water entering the engine is constant because the rise in temperyature of the water iiowing through the engine is constant. Thus, the temperature of the jacket water leaving the lubricating oil heat exchanger or cooler is constant and as the amount of heat l dissipated to the jacket water from the lubrieating oil in the lubricating oil heat exchanger is constant, the temperature rise of the jacket waterand lubricating oil'to and from the lubricating oil heat exchanger remains constant. Thus, regardless of changes in the temperature and quantity of the sea water, at any given engine power the oil and jacket water temperatures to and from the engine are maintained absolutely constant which is a very desirable the amount of heat dissipated into the jacket water by the operation oi the engine is about ten times the amount oiA heat dissipated into the lubricating oil and, therefore, thejacket water is heating very much more rap'dly than the lubricating oil upon starting a cold engine provided that'the jacket water is constrained to by-pass the jacket water cooler.. As the jacket water temperature becomes elevated to the operating'range, the control element of the threeway temperature control valve in `thermal contact with the heated jacket water tends-to throttle the ilowof jacket water throughthe bypass and force sumcient jacket water through the jacket water cooler .to maintain a constant predetermined temperature of the jacket water leavng the engine, regardless oi' the temperature of the sea water circulated through the ,jacket water cooler and regardless ofv variations in the power being generated by the engine.

` With a constant temperature maintained in the jacket water leaving the engine through the operation of the temperature control valve-it will be noted that, at any given engine power,

engine operating condition from the standpoint of engine service life and reliability.

In certain installations and under certain cond'tions it may be found to be desirable to. provide a jacket water by-pass pipe 33 having a fixed restricted orifice 34 therein and establishing communication directly from the jacket Water discharge pipe I8 and the jacket. Water inlet pipe 22. The flow of water through this bypass is automatically controlled'by the xed oriilce 34, although in some cases it might be desirable to substitute a manually controlled valve in lieu of the iixed oriilce 34. This modified system has all of the advantages asithe system hereinbefore described as to the rapid heating oi' chilled lubricating oil on starting and automatic control of lubricating oil and jacket water temperatures. An additional advantage associated with this modiiled system applies to engine ,installations where it is desired to provide for a relatively small risein temperature of the jacket water iiowing -through the engine and also to reduce the size of, the lubricating oil heat exchanger to the minimum at the expense of a slight increase in thesize of the jacket water cooler. v

By means of the iixed by-pass arrangement, `a predetermined quantity of heated jacket water is automatically by-passedaround both coolers. The remaining jacket water is cooled to a lower temperature than would be obtained if the entire quantity of jacket water were circulated through the jacket water cooler. Thus, relatively cold water is circulated through the lubricating oil heat exchanger and the size of this unit can therefore be reduced as compared to e the size required ii warmer water were circulated through this heat exchanger.

The uncooled jacket water iiowing through the `fixed orifice 34 l'n the by-pass pipe 33 mixes with the cooler ljacket water discharging from the a lubricating oil heat exchanger and/ the resulting mixture owing to the engine is warmer than would normally be obtained ii' the full quantity -of jacket water. were passed through the two i heat exchangers. By properly proportioning the size of the heat exchangers and that of the by-pass 33 and nxed orifice Il it ls'possible to gine installations.

From the foregoing it will be apparent that a very eilicient system is provided for controlling the temperature of both the cooling water of the engine and the lubricating oil thereof by means of which the service life of internal combustion engines is materially extended, the reliability of the engines is improved and the neces--` sity for maintenance and repair decreased. Also, the improved system insures the rapid heating of chilled lubricating oil upon vstarting a cold engine and the rapid warming up of a cold engine upon starting. The temperatures of the jacket water and lubricating oil is controlled entirely automatically. The lubricating oil heat exchanger is not subjected to the corrosive action of sea water. The improved system permits of a simplified piping arrangement with only one automatic control valve necessary for the regulation o-f the temperatures of both the jacket water and the lubricating oil. The system has the additional advantage of providing for relatively small temperature rise of jacket water circulatedthrough the engine with minimum size of lubricating oil heat exchangers.

IIt will be understood that, whereas the abov description of the present engine cooling system is particularly adaptable to marine engine ,in-

stallations it is equally applicable to all other.

internal combustion engine installations. For land installations the term sea water as employed herein may be more properly termed raw water or a cooling fluid obtained from an external source and for aircraft insallations the primary cooling medium is. air. It-will also be understood that the control element 28 of the three-way temperature control valve I9 may be located at various other points in the jacket p water circuit or in the lubricating oil circuit with generally` similar results depending on proper design and adjustment of the automatic control feature. Also, thethree-way temperature control valve I9 may be located at the opposite end of the jacket water cooler by-pass pipe 26 or at either end of a sea water by-pass pipe around the jacket water cooler or a manually controlled valve may be employed in lieu of an automatically controlled valve. It will be understood further that a two-way temperature ,control `valve may be substituted for the threeway valve shown with similar results provided that the cooling system is proportioned so as to provide for relatively small pressure drop through the jacket water by-pass pipe 26 as compared to the pressure drop through the jacket water circuit of the jacket water "cooler,

It will be understood, as previously stated, that the above description and accompanying drawing comprehend only the general and preferred embodiment of the invention and that various changes in construction, proportion'and arrangement of the parts may be made within the scolpe of the appended claims without sacrificing an of the advantages of the invention.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is -claimed is:

1. A system for controlling the temperature of the cooling water and that of the lubricating oil for an internal combustion engine wherein a rst heat exchanger cools the water flowing from the engine and a second heat exchanger through which lubricating oil from said engine is circulated, the heat transferring capability of which is controlled by the water flowing from said first heat exchanger, controls the temperature ofV said lubricating-oil; characterized by the fact that'there is combined with said first 'heat exchanger, means for by-passing the heated Water owing from the engine cooling system aroundsaid first heat exchanger for delivery directly to said second heat exchanger in -a heated condition in order to elevate the temperature of said lubricating oil.

2. A system for controlling the temperatur of the cooling Water and that of the lubricatil oil for an internal combustion enginewherein a first heat exchanger cools the water flowing from the engine and a second heat exchanger through which lubricating oil from said engine is circulated, the heat transferring capability of which is controlled by the Water flowing from said first heat exchanger, controls the temperature of said lubricating oil; characterized by the fact that there is combined with said first 4heat exchangermeans for by-passing a portion of the heated water flowing from the engine cooling system around said first heat ex changer for delivery directly to said second heat exchanger in a heated condition to maintain the engine lubricating oil at the desired operating temperature.

3. A system for controlling the temperature of the cooling water and that of the lubricating oil for an internal combustion engine wherein a first heat exchanger cools the Water flowing from the engine and a second heat exchanger through which lubricating oil from said engineV is circulated, the heat transferring capability of which is controlled by the water flowing from said first heat exchanger. controls the-temperature of said lubricating oil; characterized by the fact that there-is combined With said first .heat exchanger, means' for oy-passing a portion of the heated water flowing from'the engine cooling system around said rst heat exchanger for delivery directly to said second heat exchanger in a heated condition to maintain the engine cooling water and the engine lubricating oil at the desired operating temperature. y

4. A system for controlling the temperature of the cooling water and that of the lubricating oil -for an internal combustion engine wherein a first heat exchangerl cools the .water flowing from the engine and a second heat exchanger through which lubricating oil from said engine is circulated, the heat transferring capability of which is controlled by the water flowing from .said rst heat exchanger, controls the temperagine lubricating on at the desired operai-.ing temperature.

5.l A system for controlling the temperature of the cooling water and that of the lubricating jwhich is controlled by the waterowing from said irst heat exchanger, controls` the temperature of said lubricating oil; characterized by the fact that therais combined with said first heat exchangena thermally controlled. means for bypassing the heated water flowing from the engine cooling system around said rst heat exchanger for delivery directly towsaid second heat exchanger'in arheated condition to maintain the engine cooling water and the engine lubricating oil at the desired operating temperature.

6. A system for controlling the temperature of the cooling water and thatof the lubricating o il for an internal combustion engine wherein a 'rst heat 'exchanger coolsthe water flowing from the engine and a second heat exchanger, the heat transferringcapability of which is controlled =by the water owing from said rst heat thereof, thus to maintain the engine lubricating oil at the desired operating temperature, and

Aineens for lay-passing a. portion of the Yheated water owing from said engine cooling system around both of said heat exchangers for delivery directly back tosaid engine cooling system, to

permit the temperatureof said lubricating oil to -be reduced it desired below the temperature of the engine cooling water entering the engine.

lli

- exchanger, controls the temperature of said lu- -liricating oil; characterized by the fact that 7. A system for controlling the temperature of the cooling water and that of the lubricating oil for an internal combustion engine wherein a iirst heat exchanger cools the water owlng from the engine and a second heat exchanger,

the heat transferring capability of which isconfor -by-passing a portion of the heated Water owing from said engine cooling system around both oi? said heat exchangers for delivery directly back to said engine cooling system, to permit the temperature of said lubricating oil to be reduced if desired below the temperature oi' the engine cooling water entering. the engine.

8. A system for controlling the temperature of the cooling Water and that of the lubricating oil for an internal combustion engine wherein a first heat exchanger cools the water owing from the engine anda second heat exchanger, the heat transferring capability of which is controlled by the water flowing from said first heat exchanger, controls the temperature of said lubricating oil; characterized by the fact that there is provided means for by-passing a portion ofthe heated water owing from said engine cooling system around both of said heat exchangers for delivery directly back to said engine cooling system, to permit 'the temperature .40 of said lubricating oil to be reduced if desired below the temperature ofthe engine cooling water entering the engine.

THOMAS J. BAY. 

